Roost making in bats-adaptations for excavating active termite nests

Abstract

The breadth of an animals' ecological niche is circumscribed by its morphology, performance, and behavior, 3 factors that can ultimately affect fitness. We investigated potential behavioral and performance adaptations to roost making, a life-history trait associated with high fitness in the insectivorous bat Lophostoma silvicolum. Males of this species use their teeth to excavate roosts in active termite nests, which we found to be much harder than the hardest prey in the bats' diet (beetles). We compared roost making and feeding behavior in L. silvicolum. We also compared the feeding behavior of L. silvicolum to that of 2 similar species that do not excavate roosts. All 3 species predominantly used bilateral bites centered on the premolar and molar teeth to eat beetles. In contrast, L. silvicolum used mainly bilateral bites involving the incisors and canines for roost excavation. All species generated similar bite forces during biting behaviors associated with feeding, but L. silvicolum generated significantly higher bite forces during biting behaviors used for roost excavation. We found no difference in canine tooth wear between the sexes, but tooth wear was significantly higher in an ecologically similar species that does not excavate roosts. We conclude that the behavior, performance, and possibly morphology of L. silvicolum represent adaptations to roost excavation. © 2009 American Society of Mammalogists.